Defined Benefit and Other Postretirement Benefits - Additional Information (Details) - Trustmark Capital Accumulation Plan [Member] - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2016	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Years of service required to vest	3 years
Subsequent Event [Member]
Defined Benefit Plan Disclosure [Line Items]
Trustmark's minimum required contribution to Trustmark Capital Accumulation Plan		$ 0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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